In a blender or food processor, blend avos until smooth. In a small skillet over medium heat, saute the shallots in the oil until tender and almost translucent but not browned. Sprinkle chili powder and set aside to cool. In a large bowl, whisk together avocado with stock and soy milk. Add shallot mixture and whisk until smooth. Stir in sea salt and pepper to taste, maybe some hot sauce. Chill for 45 minutes, garnish with tomato.